Automatic nailing apparatus

ABSTRACT

A machine or apparatus for laying wood floors, particularly in large areas, such as gymnasiums, is provided having a wheeled, frontwardly positioned floor board aligning and nailing unit and a wheeled, aligned, backwardly positioned, guide and positionadvancing and setting unit for the nailing unit. The nailing and guide units are adjustably coupled together and actuated in synchronism for back and forth movement along the floor area. The apparatus can be controlled in its operation by manual means, by automatic electric switch control means, by valve means or any combination of such means and is adapted to move back and forth across a room in alignment with a previously laid longitudinally extending run of floor members. A detachable, wheeled control unit is shown for alternative mounting on leading sides of the nailing unit during its back and forth movements along a floor area. Position change and locator means is connected between the nailing and control units to vary their spaced relation as the nailing operations progress. The apparatus can be progressively advanced and set to provide a desired abutting or clearance spaced relationship between adjacent floor board runs; it has a fluid motor operated hammer for assuring a proper nailing positioning of a floor board of a run.

22 Filedz United States Patent 1 Thompson AUTOMATIC NAILING APPARATUS [76] Inventor: Einar T. Thompson, 107 White Gate Rd., Pittsburgh, Pa. 15238 June 23, 1971 [21] Appl. No.: 155,891

Primary Examiner-Granville Y. Custer, Jr. Attorney-Green, McCallister & Miller [57] ABSTRACT A machine or apparatus for laying wood floors, particularly in large areas, such as gymnasiums, is provided Oct. 9, 1973 having a wheeled, frontwardly positioned floor board aligning and nailing unit and a wheeled, aligned, backwardly positioned, guide and position-advancing and setting unit for the nailing unit. The nailing and guide units are adjustably coupled together and actuated in synchronism for back and forth movement along the floor area. The apparatus can be controlled in its operation by manual means, by automatic electric switch control means, by valve means or any combination of such means and is adapted to move back and forth across a room in alignment with a previously laid longitudinally extending run of floor members. A detachable, wheeled control unit is shown for alternative mounting on leading sides of the nailing unit during its back and forth movements along a floor area. Position change and locator means is connected between the nailing and control units to vary their spaced relation as the nailing operations progress. The apparatus can be progressively advanced and set to provide a desired abutting or clearance spaced relationship between adjacent floor board runs; it has a fluid motor operated hammer for assuring a proper nailing positioning of a floor board of a run.

1 26 Claims, 31 Drawing Figures u 1 I 1 I I I 1 I I l I 1 111 I ,1 1111! 11111111111! II\ I I I Patented Oct. 9, 1973 7 Sheets-Sheet 1L INVENTOR. E/nar 7. Thompson ZMJICW H/S ATTORNEYS Patented Oct. 9, 1973 '7 Sheets-Sheet :5

a; r -47b' /48 INVENTOR.

Einar 7? Thompson m M I 47 u %wil aw HIS ATTORNEYS Patented Oct. 9, 1973 3,764,053

'7 Sheets-Sheet 1 6 Iii] H6 E/nar Z Thompson Fig. /5 g i H/S ,4 TTORNE Y5 Patented Oct. 9, 1973 7 Sheeis-Sheet 2' INVENTOR. Einar 7: Thompson HIS ATTORNEYS AUTOMATIC NAILING APPARATUS CROSS REFERENCE TO RELATED APPLICATION With reference to representative means for operating nailing and hammering units, a general type of operating circuit arrangement such as illustrated in FIG. 1 of my copending application Ser. No. 824,226, filed May 13, 1969, now U.S. Pat. No. 3,619,895 of Nov. 16, 1971, entitled Nailing Machine for Wood Flooring, may be employed.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an automatic apparatus for quicklyv and accurately nailing floor members as crossextending runs to under-positioned supporting members, such as sleepers, joists or a sub-floor and particu' larly, to an improved nailing machine thatcan be set and accurately controlled to provide a desired secured relation between a previously laid floor member and a floor member that is in the process of being laid or nailed in place. The machine is particularly suitable for largeareas where accurate work is required, such as in gymnasiums, auditoriums, etc.

2. Description of the Prior Art A power tool such as a nailer that has to be manually carried and used is so heavy that a great amount of fatique is encountered even after a short period of usage. As a result, efficiency of the operator is soon lost as well as accuracy of the operation. Board nailing machines have been devised heretofore, but except for the apparatus of my above-mentioned application, none including those devised specifically for nailing floor members have been commercially paracticable, as indicat d by, their ask tasl pti a hith99$kilk2difl t e art. Such machines have generally been too bulky or complicated for practical utilization.

SUMMARY OF THE INVENTION ment or apparatus which will enable a full flexiblity ofoperation from the standpoint of a desired relationship between a previously laid floor member and one being laid from the standpoint of the closeness of the members with respect to each other, such as to allow clearance expansion and contraction.

Another object has been to provide a machine that will be accurate in its control and relatively simple to operate from the standpoint of the workmen.

Another object of the invention has been to provide a machine that will automatically move and maintain an aligned relationship as it advances across a room and is used to nail a run or course of board members in position on suitable supporting joists, channels, etc.

A further object of the invention has been to provide nailing apparatus in which manual operations are minimized and which enables an automatic, progressively advancing nailing movement in a fully accurate and aligned relationship with respect to the floor area of the room.

A further object has been to devise an apparatus having a control unit whose relationship with a forwardly positioned nailing unit may be adjusted as nailing operations progress.

A still further object of the invention has been to provide a nailing machine that will automatically stop its motor-driven advancing movement in the event that a floor member is not available for nailing.

These and other objects of the invention will appear to those skilled in the art from the illustrated embodiment and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, FIG. 1 is a side view in elevation illustrating a board aligning and nailing unit of apparatus incorporating the invention and in an operating position for nailing a floor member in position with respect to a previously laid floor area;

FIG. 2 is a bottom plan view on the scale of and of the apparatus of FIG. 1; j

FIG. 3 is a front end view in elevation and FIG. 4 is a rear end view in elevation on the scale of and of the apparatus shown in FIGS. 1 and 2;

FIG. 5 is a fragmental horizontal section on the scale of and taken along the line VV of FIG. 1; this view particularly illustrates the resilient or flexible mounting of a nailer of the apparatus of FIGS. 1 and 2;

FIG. 6 is a greatly enlarged fragmental side section particularly illustrating the completion of a nailing operation and a partial withdrawal of the nail-driving blade or pusher of the nailer;

FIG. 7 is a side view in elevation on a slightly enlarged scale and FIG. 8 is an end view in elevation on the same scale as FIG. 7 and illustrating a removable rim construction that may be used for wheels of any of the driven units of the present invention to accommodate for different thicknesses of wood flooring members to be laid;

FIG. 9 is a side view in elevation on an enlarged scale with respect to FIGS. 1 and 2 illustrating a sidepositioned motor-drive-controlling and travel-areasensitive wheel unit that may be detachably connected to either side of the apparatus of FIGS. 1 and 2 for controlling the operation of its nailer unit as well as for stopping its floor traversing movement when an additional floor board is required along a floor run;

FIG. 10 is a top plan view in partial section on the scale of and of the apparatus of FIG. 9;

FIG. 1 l is an end view in elevation on the scale of and taken in the direction of the arrows Xl-XI of FIG. 9;

FIG. 12 is a side view in elevation on the scale of FIGS. 9 to 11, showing a smaller diameter of traveling wheel and a modified form of nailer operating cam construction;

FIG. 13 is a side view in elevation on the scale of FIG. 1, with some parts omitted to better illustrate operational parts of lifting or tilting means; in this view, the nailer unit is shown in a forwardly upwardly raised or tilted position as accomplished by the tilting means;

FIG. 14 is an end section in elevation on the scale of and taken along the line XIV-XIV of FIG. 13',

FIG. 15 is a side view in elevation on the scale of FIG. 1 and illustrating a control unit adapted to be hitched or connected to the unit of FIG. 1 in a backwardly aligned and cooperatively associated relationship with respect thereto; this machine or unit has means for positively guiding it, and thus the connected unit of FIG. 1 across or along the width of a floor area, and also for advancing the machine of FIG. 1 one board forwardly after a run of flooring members or boards has been nailed in place preparatory to nailing a second run in place;

FIG. 16 is a horizontal section on the scale of and taken along the line XVIXVI of FIG. this figure shows a draw bar of the control apparatus or unit in a same forward stroke position as in FIG. 15; the motor support and chain have been omitted for clarity of showing of other structure of FIG. 15;

FIG. 17 is a bottom plan view of the unit of FIG. 15; this view shows the draw bar of the apparatus in the same position as FIG. 16;

FIG. 18 is a front view in elevation on the scale of and of the control unit or machine of FIG. 15;

FIG. 19 is a vertical fragmental section on the scale of and taken along the line XIXXIX of FIG. 17, particularly illustrating the mounting construction of a slidable draw bar;

FIG. 20 is a top plan view of a position-locking unit and of a channel-shaped connector bar assembly suitable for utilization between the units of FIGS. 1 and 15; this figure is on a slightly enlarged scale with respect to such figures;

FIG. 21 is a side section in elevation on the scale of FIG. 20 and of the assembly of such figure; these two figures show the connector assembly in its maximized telescopically closed or minimum length relationship, as may be employed when the nailing apparatus of the invention is being started in its floor laying operation;

FIG. 22 is a fragmental side view in elevation on the scale of FIG. 21 and showing the position locking unit in a raised or unlatched position;

FIG. 23 is an end section in elevation on the scale of and taken along the line XXIIIXXIII of FIG. 21;

FIG. 24 is a view similar to and on the scale of FIG. 21, but showing channel-shaped connecting bars of the assembly in a one-step expanded relation with respect to each other which may be accomplished after one board run has been nailed and a next succeeding board run is to be nailed;

FIG. 25 is an enlarged end section in elevation along the line XXV-XXV of FIG. 21, and FIG. 26 is a similar end section on the same scale and along the line XXVI- --XXVI of FIG. 21;

FIG. 27 is a top fragment on the scale of FIG. 20 particularly showing the end connecting means for connecting the bar assembly to the connector bar of the nailing unit;

FIG. 28 is a side view in elevation illustrating a modified form of connecting assembly in the nature of an A- frame between nailing and control units which may be used initially to enable a closer operation with respect to a back wall of a room than the assembly shown in FIGS. 20 and 21; after the unit of FIG. 28 has been expanded to its maximum expanded relation, then an assembly such as shown in FIGS. 20 and 21 may be utilized to extend the area of coverage;

FIG. 29 is a horizontal section on the scale of and taken along the line XXIX-XXIX of FIG. 28;

FIG. 30 is a schematic top plan view showing an overall apparatus assembly embodying the assembly of FIG. 20 as utilized in nailing a cross-extending floor member with respect to a previously laid cross-extending run; and

FIG. 3l'is a circuit diagram and fluid flow schematic showing an operating system for apparatus of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus illustrated utilizes a forwardly positioned nailing unit A having, as shown in FIGS. 1 and 2, an upright support frame structure 10 which carries a board-positioning bumper or hammer head 78 and a nailer 42 having a head 50 (see FIG. 6) for securing a length of wood flooring member 7' (shown as of a tongue and groove type) on or across floor sleepers, joists or channels 5 or on a sub-floor 6. In FIG. 1, the frame 10 is positioned for rolling movement back and forth along a starting area of a floor C that is being laid, or longitudinally of an endwise-aligned run or course of wooden boards or floor members 7' that are to be properly aligned, positioned and secured with respect to a previously nailed line or run of adjacent floor members 7. A pair of supporting rollers l5, 16 is mounted on each side of the frame 10 and on opposite ends of an associated one of a pair of forwardly extending, sidepositioned drive shafts 17. The back roller 16 of each pair is shown of narrower width than the associated wide-track front roller 15; the front roller 15 has a width substantially corresponding to the width ofa pair of sidewise-abutting and interfitting floor boards such as 7 and 7 (see FIG. 1). Each drive shaft 17 is journaled within a pair of spaced-apart bearings 20, 20' and is held in operative alignment therewith by a pair of set screw mounted collars 18a and 18b (see FIG. 2).

Each drive shaft 17 for an associated pair of rollers 15, 16 carries a chain sprocket 22 centrally thereof for actuating it. A cross-extending electric motor M such as of a geared speed-reducing reversible, direct-current type, has an output shaft 26a on which a drive sprocket 25 is mounted. As shown particularly in FIGS. 1, 2 and 4, the drive sprocket 25 interleaves or meshes with a continuous chain 23 that is also interleaved over the sprockets 22 of the side-positioned drive shafts 17. Thus, the electric motor M may be energized to move the front aligning and nailing unit A of the apparatus in either direction or back and forth along previously laid floor members 7 of a room floor structure C. The support frame 10 for the front unit A has a pair of inclined, transversely spaced-apart, front guide and aligning rollers 35 that are peripherally grooved at 3511 (see FIG. I) to fit over the tongue portion of and along an outer longitudinal side of a floor member 7' that is being laid. Each guide roller 35 of the pair is journaled on a stub shaft 36 that projects in a forwardly downwardly inclined relation (shown as about 9'/z off the vertical from the front end portion of the support frame 10). The upper end of each shaft 36 is threaded to receive a nut 36a for securing it in position on slightly angled mounting portion of a platform or floor 11 of the frame 10. In the figures, 11a, 11b and 11d represent cut-out portions in the platform 11 for accommodating floor rollers 15 and 16, sprockets 22 and an angle shaped lift member 34 to be described. As shown, the frame structure 10 has spaced-apart front and back pairs of upright members or legs 12 and 13, respectively. Motor M has a mounting flange 26b that is secured on an auxiliary platform 28 by bolts 27. As shown in FIG. 1, the auxiliary platform 28 is secured on the main platform 1 l by means of spaced-apart, upright lugs or fingers 29.

The nailer unit 42 which may be of a commercial type, such as manufactured by Pasalode Company Division of Signode Corporation of Skokie, III., as its Bronco 91030, may be used and is shown mounted by a pair of opposed, reinforcing side pieces43 that carry a pair of pivot pin or stub shafts 44. The shafts 44are swingably mounted on a pair of forwardly extending side brackets or wings'45' and 46: to extend or slope backwardly from the frame at the front end of the unit A, between the guide rollers 35. The nailer unit 42 has been modified to provide its housing with an upper, continuous side flange 52 on which a top cover member 53 is removably secured by peripherally spacedapart bolts 54. This facilitates inspection and repair of the nailer 42. As shown in FIGS. 1 and 3, four bolts 54 mount the plate 53 on the end of the nailer unit 42. This allows the lower end of the nailer to move parallel to the run of the flooring and its driving blade 51 to momentarily follow a nail 8 as it is driven into the flooring (see FIG. 6). This mounting is similar to or corresponds to the mounting of the nailer 27 in my U.S. Pat. No. 3,619,895, in that the nailer unit 42 is permitted to have a follow-through swing on the stud shafts 44 during the driving operation. Feed delivery magazine 40 for nail or clip groups is provided with a side-mounting holder and spring-loaded follower 41. The follower 41 (see FIG. 1) carries an angle piece 41a thereon to engage and open a spring-loaded slide switch 40a when the follower has reached the lower solid line position of FIG.'1, thereby indicating that the usable supply of nails or staples has been substantially exhausted. The switch 40a is normally closed, but when opened to open line a of the circuit of FIG. 31, it immediately stops the operation of drive motors M and M When a new clipof nails or the like is inserted and the follower 41 is at-its upper dot and dash position of FIG. I, the switch 40a will again be in a closed position.

i The unit A also has a swingable arm 75 whose lower leg portions 75a support and carry the bumper or hammer head 78 which is adapted in its down stroke to hit the front end of the support frame 10 to transfer driving force to the front guide rollers 35 and hammer ordrive a boardmember 7' into a fully aligned and proper tongue and groove interfitting relation with a board member 7. The hammer head 78 serves asan impact meansthat is complementary with the cylinder P for assuring that arun of the frontmost floor members 7' is nailed in a proper interfitting and aligned relation with a run of previously laid and nailed floor members 7. Theoperation of the motor or cylinder P, provides, in effect, a resilient means which allows take-up movement of the unit A when, for example, the hammer 78 strikes it to assure that an immediate board 7 to be nailed is in its fully in" position shown in FIG. 1. As

the platform 115 of unit B.

The nailer unit 42 is resiliently held in a central position on its pair of mounting pivot pins 44 (see FIG. 1) by a pair of side-positioned coil springs 55 (see FIG. 5) which are carried inan opposed relation by opposite pairs of mounting cups 12a, 42a. The cups are respectively carried by upright frame members 12 andby the housing of the nailer unit 42. This resilient, springcentered mounting enables the nailer unit 42 to slightly pivot or swing to start and finish its nailing operation, without damage to a nail 8 (see FIG. 6) that is being driven and without stopping the sidewise movement of the unit A or interfering with its continuous operation.

upper end portion of the support frame 10. A clevis or bifurcated mount7l (see FIGS. 1 and 4) is secured to extend downwardly from the inside of a top cover member 14a and pivotally carry the back end of the motor P through the agency of backwardly projecting lug a and a pivot pin 72. The motor P; has a forwardly extending piston rod 73. The forwardend ofthe piston rod 73 has a connectorportion 74 that connects it to a clevis end 73a that is pivotally secured by pin76 to the upper end of swingable, dog-leg-shaped hammer arm 75. Lower, longer length leg portionlaof the hammer arm 75 carry transversely-extendingbumper or hammer head 78 which may be constructed'of hard rubber or other suitable material. The. hammer arm75 is operatively carried by pivot shaft 77 on vertical members 12 of the support frame l0to extend between the front pair of floor member engaging guide rollers 35, forwardly thereof.

The nailer 42. extends backwardly within the frame 10 to periodically drive-in a nail 8, shown particularly in FIG. 6, that is fed from the nail-carryingmaga zine 40 that is secured within the frame 10 and extends to a nailing head 50 (see FIG. 6). Spring-loadedfollowerml is carried by the magazine 40to automatically feed a nail each time the head 50 and driver blade 51 of the nailer 42 move towards a downward-backward: driving position. The switch 40:: may be opened when only about five or six nails or staples remain in the magazine 40. As shown in FIG. 31, switch40a is normally closed.

When exposed beams or joists 5 are present, the operation of the nailer 42 may, as setforth in my US. Pat. No. 3,619,895, be controlled automatically by. a switch 37 in FIG. 1 that is operated by a feeler finger'37a that is positioned forwardly of the unit A on an angleshaped front cover member 14b. The switch 37may be used instead of the switch S of wheeled control unit D of FIG. 9 to when closed, electrically energize a solenoid (such as C,) to open control valve V for introducing a positive flow of fluid into fluid-operated cylinder or motor P of the nailer 42. If desired, also as set forth in my prior patent, a positive fluid flow may. be introduced at this time into fluid cylinder or motor P to operate the hammer head 78. The switch 37 may be closed when the feeler 37a periodically engages the side of a joist5, as the machine or apparatusis being;

moved transversely along or across the floor area C.

However, the employment of a wheeled side-positioned control unit D (see FIGS. 9 to 12 provides a spacedapart control of' nailing operations irrespective of whether or not asub-floor 6 is used. Thus, the feeler switch means 37, 37a may be eliminated.

When valve V islopened by the electrical energization of solenoid C by a manual closing of the switch S, or an automatic closing of the switch S ot FIG. 31' (see also FIG. 37 of FIG. 1, positive fluid flow is supliedfrom line i to thefluid cylinder or motor P, to actuate the nailer 42 to drive-a nail8fedfrom the magazine 40. Piston rod 560 of fluid motorP earries a clevis 57(see FIG. 1) on its end to which a trigger connector member 58 is pivotally connected by a pivot pin 57a. A springpressedtrigger member 59 has a finger 59b (see FIG. 4), and is pivotally connected by pin 58a to the other end of the connector member 58, and carries a shaft portion 59a. The shaft portion 59a is rotatably carried within a slotted opening 60a in a support shelf member 60. The shelf 60 is securedat its inner end to extend outwardly from an L-shaped bracket member 61 that forms a part of the frame structure 10. A platform 62 is secured on leg portions of the member 61 to project upwardly therefrom and mount the fluid motor P thereon. When trigger finger 59 is depressed against spring tension, it closes the valve V and connects the cylinder of the fluid motor P to exhaust line j; at this time, spring biasing on the fluid motor P causes it to return to its upper starting position wherein the piston 56a is withdrawn and the driver blade 51 50 of the nailer 42 is returned to its upper starting position.

The frequency of the operation of the hammer head 78 may be controlled by a switch 8,, as used in combination with and operated simultaneously with nailer operating switch 37 of FIG. 1 or switch S, of FIGS. 9 and 31. Also, the switch S may be manually operated or a purely manual switch may be submitted to provide for manually controlled operation of the hammer if it should be desirable. It will be noted that in the circuit diagram of FIG. 31, S., and 8;, represent alternately used switches, in the sense that switch 37 may be used in the circuit at the location of S when the apparatus is being employed to directly lay flooring on exposed joints. A switch S may be used when the apparatus is being employed to lay flooring on a previously laid subfloor. The operation of the hammer may also be effected by a micro switch S when a floor board of a run being nailed has not been properly seated. If the floor boards 7' to be laid have absorbed an excessive amount of moisture and have accumulated a wider distance than the connector assembly, spacer bar or rod assembly between units A and B will permit, this will force unit A forwardly with respect to unit B, causing piston rod 143 to advance or extend slightly with respect to shifter cylinder P, to thereby cause side-projecting finger or lug 67a to close or activate the micro switch S (see FIGS. 16 and'3l). The operation of the hammer head 78 will force the board 7 into a proper position, such that it can thereafter be secured by nailing in accordance with the outlined procedure. The cylinder P, acts like a shock absorber and returns to its initial position thereafter, thus causing the other parts to assume their normal working positions.

Driving wheel pairs and 16 of the unit A may, for example, be set-up for nailing 25/32 of an inch of floor thickness and then adapted to 33/32 inches of floor thickness by removing one-fourth inch thick steel rim flanges or tires thereon, see particularly FIGS. 7 and 8. The most popular thickness of flooring used is and lb 33/32 of an inch. The tongues and grooves of both thicknesses are the same size and have the same distance from the bottom of the boards. Thus, the nailing head 50 will be in the same position for both thicknesses. The distance from the top of the board 7 being laid to the bottom of the plate 11 of unit A thus only changes by one-fourth of an inch. The rims are shown as having two semi-circular halves 47 and 47' that are removably secured together by machine screws 48. The screws 48 are illustrated as entered along slots 47a in one rim half 47 and are threaded to fit within threaded bores 47b of the other rim half 47'. The apparatus can thus be adapted to different thicknesses of wood or floor members by varying the diameter or sizes of the two pairs of driving wheels of the unit A. In this connection, the wheels l5, 16 may have one or more sets of removably clamping tires in order to quickly adapt them without substituting various sizes (diameters) of wheels for this purpose. The width of the rims will preferably correspond to the respective widths of the drive wheels l5, 16.

The nailing operation is accomplished by moving the apparatus from right to left and from left to right across the room or space following the run of the floor boards. That is, the nailer unit A is reversible in its movement along the floor C, as actuated by drive motor M and is operative in nailing a course or run of boards 7, whether it is moving in one direction or the other across the room. The frequency of the nailing action, instead of being controlled by a micro switch operating whisker or feeler finger 37a, may be accomplished by employing an interchangeable cam 97 or 97 (see FIGS. 9 and 12). Thus, as shown in FIGS. 9 to 11, a cam and feelepoperated switch S, may be carried by demountable, side-positioned wheeled control unit D and operated in a position-spaced relation to actuate the nailer 42 each time it reaches an aligned relation with a joist member 5 or has moved a spaced distance along previously laid subflooring.

The control unit D has been provided for detachable or quick demountable mounting on each platelike side wall 14d which with top wall 14a, front end wall 14b and back end wall 14c, defines enclosing housing or casing 14 of the nailer unit A. As thus used, the unit D serves as a wheeled leading unit for the nailer unit A in its movement back and forth across the room that is being floored, with its wheel adapted to ride on a completely nailed floor member 7 and its feeler finger 103 adapted to ride on a floor member 7' that has been newly laid for nailing in position. The feeler 103 is adapted to shut-off the drive motor M of the unit A through the agency of a micro switch S, when, as shown by the solid lines of FIG. 9, the feeler finger 103 moves off the end of a board member 7' that is being laid. The dot and dash lines of this figure show the normal position of the finger 103 when the machine is operating or moving along the floor. In other words, the switch Sserves as stop switch for movement of the nailing unit A when a worker has neglected to insert the next floor member or piece of members 7' that are to be nailed by one direction of sidewise movement of the apparatus along the width of the floor C. A conventional delay timer may be used with the switch S, to give a workman full opportunity to align a new board member 7' that is being laid. Such delay. timer may be of any suitable commercially available type, such as one which requires a short period of heating up current flow to cause full current full current flow to a main element to be energized.

The operator, of course, inserts the board 7' beneath the feeler 103 and thus causes it to move from the full line position of FIG. 9 to the dot and dash position thereof. This would immediately cause the mechanism to be energized if a timer was not used to provide a slight delay for permitting the proper insertion of the board member.

In operating the nailing unit A with a detachably mounted, side-position, movement and switch control or operating unit D, a manual forward stop reversing switch means (not shown) may be provided in series with the feeler operated switch S and is opened to stop the drive motor M when the coupled units A and B have approached to within a few feet of a side wall of the room. Then, the unit D to the other side of the unit A and the drive motors are thereafter activated by closing the manual switch means to complete movement of the units close to the side wall. Feeler 107 of a second micro switch S, will periodically engage the cam 97 or 97 during the movement of the unit A to operate the nailer 42 on the basis of the distance transversed by the wheel 95 of the unit D, representing, for example, the distance between apair of adjacent joists 6. FIG. 9 shows a double face cam 97 suitable for effecting a nailing switch operation for a ten inch spacing of joists 5 (using a wheel 95 of inches circumference) and FIG. 12 shows a single face cam 97' suitable for a twelve inch spacing of joists 5, using a wheel 95 of smaller circumference, compare FIGS. 9 and 12.

The control unit D of FIGS. 9 to 11 has a pair of spaced-apart slide mounts 90 that are secured on the end of a transverse mounting shaft 92, as by weld metal w. The inner end of each mount 90 is provided with a pair of spaced-apart slide flanges 91 that define a valley therebetween. Each side plate member 14d of the unit A has a rectangular, vertically extending pair of slots 85 therein which are enlarged at their upper ends and reduced at their lower ends. The enlarged upper portion is the portion adapted to initially receive the flanged ends of each mount 90, and the reduced lower portion is adapted to provide a complementary slide fit with the groovebetween each pair of flanges 91. To retain the mounts 90 in position, a swing finger or locking dog 86 that is pivoted at 87 on the side wall plate 14d is adapted to be swung downwardly by its outwardly projecting grip pin or handle 88 to close-off the upper and wider portion of each slot 85. When the unit D is to be removed from one side wall plate member 14d, then the locking dog 86 is swung upwardly to rest against a pin 89 (see FIG. 11) and, at this time, the entire unit D can be lifted out of its mounted relation by sliding its back end portion and particularly, its mounts 90 upwardly into the wider portion of each latching slot 85 and then moving the unit outwardly. At this time, the unit D may be moved over to the other side of the nailing unit A and the mounting operation repeated, ready for the movement of thenailing unit A in an opposite direction across the room of the building.

The unit D has a swingable arm 94 on which a floorengaging wheel 95 is mounted. This swing arm 94 is adapted to extend from the side plate 14d of theunit A in such a manner that the wheel 95 will move along the floor C in the direction of the board or flooring runs. Of the two feeler-operated micro switches S and 8,, one 8, projects along the swing arm 94 into the path of rotative movement of cam 97 that is carried for rota-- tion on a wheel shaft 96. The cam 97 provides an engagement with flexible feeler 107 of the switch S in a timed relation such that the nailer 42 is always at or is immediately adjacent a joist 5 to which a floor board 7' is to be nailed. The swing arm 94 represents a longitudinally extending central body portion that is provided with a backwardly extending, integral, swingmounted arm portion 94a. The upper endof the arm portion 940 has a journaled fit by means of a sleeve bearing 93 centrally of and of the mounting shaft 92.

A pair oflimit pins 920 retain the arm 94a in its central positioning on the shaft 92 for swinging movement with respect thereto.

It will be noted that the switch S is adjustably mounted on an upstanding, wheel-carrying plate member 100 that is pivotally mounted on the forward end of the arm member 94 by cross-extending shaft 96 and a key 99 (see FIGS. 9 and 11). In this connection, the plate 100 has a pair of enclosed and elongated vertical slots 1001; and 1000. The micro switch S has side mounting tabs 101a that adjustably secure it on the face of the upright member 100 by bolt and nut assemblies 102 that fit within the slots 100b and 100C. This permits a suitable vertical adjustment between the switch S and wheel which is rotatably carried on the shaft 96 for rotation by frictional engagement with the floor.

The cam 97, as shown in FIG. 9, is also mounted on the shaft 96 for rotation thereon and is secured to the wheel 95 by pairs of nut and bolt assemblies 97a. In this arrangement, each end face of the cam 97 provides a camming action on a switch operating finger or flexible feeler 107 when, for example, one cam face is in abutment therewith, as shown in FIG. 9. This closes micro switch S. to activate electric solenoid C, to, in turn, provide positive fluid flow to fluidmotor P, for driving a nail 8 through a floor board 7' into a joist member 5. The micro switch S which is employed to operate the nailing unit 42 is removably secured to the arm 94 by bolts 106 in such a manner that its feeler or operating finger 107 projects in a forwardly downwardly declining direction, such that it will be flexibly bent downwardly to close the switch S each time one of the two operating end faces of the cam 97 engages it.

The upright plate member has a vertically extending, planar edge wall portion 100a that is adapted to engage in an abutting relation. with either one of a pair of centrally inwardly inclining, sloped, stop edges or shoulders 94b and 94c that are carried along one side of the arm member 94. The purpose is to limit a backward swinging movement of the plate member 100 on shaft 96 to a vertical upright position which is resiliently retained by a tension spring 110. The spring is at its one end secured by a mounting pin 111 on the housing of the switch unit S, and, at its other end, within a perforated flange portion of an angle piece 108. The angle piece 108 is secured by a threaded bolt 109 on a side of the swing arm 94. It will be apparent that the upright plate member 100 and the switch S, carried thereby is thus permitted to flexibly swing to the right of FIG. 9 on the shaft 96 when, for example, the unit D is being changed to the opposite side of the unit A. It will be noted that the motor M will only be actuated to run the unit A when the finger 103 is in an inclined position (see the dot and dash position of FIG. 9) and is deactivated when the finger 103 is in the solid line vertical position of FIG. 9 or when the finger 103 rides-off the end of a floor member 7'. The wheel 95 must always be positioned on a previously nailed board and toward the back of the unit A, as used on either side of such unit. The feeler or whisker 103 will run on a board 7' being nailed and in front of the machine in the direction of its travel, in front of the wheel 95 of FIGS. 9 and 10, and on either side of the unit A. The unit D is not inverted in the operation, only its part 94. For example, the part 100 may be held vertically and the part 94 rotated counterclockwise down and around until the edge 94c abuts the opposite side of the part 100, entailing about 225 of rotation. The spring 110 permits the member 100 to be manually swung clockwise of FIG. 9 about 225 about shaft 96 and to hold it in such a reversed position against abutment 94b when the unit D is to be moved from one side of the unit A to the opposite side thereof. The unit D is used in an upside-down position as attached to the opposite side of the unit A.

In FIG. 12, a modified form of cam 97 is illustrated as having only one operating cam face, since instead of being mounted centrally on the shaft 96 like the cam 97, it is mounted at one end portion thereof and it has only one end face.

Maple flooring, such as used in gymnasiums, is required to have a moisture content of between and 7 percent in the state of Arizona. Other places in this country require flooring of higher moisture content and thus, during the installation of maple floor, it has been customary to use spacers or washers between a pair of board runs to give a normal five-eighths expansion to each 6 feet width or transverse dimension of the floor,- ing, measuring across its grain. The highest humidity condition in existing schools in the Pittsburgh area is between 12 to l3 percent. It will be apparent that the insertion and removal of washers is time consuming, may damage the flooring during removal, and is unsightly if the flooring does not expand and close the gaps. In accordance with the present invention, the unit A is so operated by means of the unit B in order to automatically provide a one-step advance of the forward operating position of the unit A that is represented by the width of the wood piece or member 7', plus any desired clearance for expansion. For example, the advance may be 2% inches plus a fraction of five-eighths of an inch, as determined by dividing five-eighths of an inch by the number of boards contained in 6 feet of flooring width or extent. It will be apparent that the distance is determined by the length of the stroke of the piston P and by the spacing between the latching slots of the draw bar 155.

Referring particularly to FIGS. 13 and 14, means is shown for raising the nailing unit A about or on its back end to facilitate the insertion of a run of board members? after a previous run has been nailed in position. This raising or upward swing of the unit in conjunction with a forward stroke of the piston 143 of the shifter fluid motor P, of unit B, enables the guide rollers to clear the inner area in front of a previously laid run of floor members 7, and is effected by a backwardly inclined downstroke of a piston rod 30b of a fluid cylinder or motor P As shown, the motor I at the rear end of its housing, has a mounting lug 30a that is pivoted by a pin 31a on a clevis 31 that is mounted on and extends backwardly from one of the upright frame members 12. The outer end of the piston rod 30b has an operating head 300 that is swingably mounted on an upper foot portion 32a of a swing crank arm 32 and retained thereon by means of a pair of through-extending pins 32b (see particularly FIG. 14). The crank arm 32 has a lower foot portion 320 which is swingably carried within an upwardly projecting bifurcated or forked mounting bracket 33 and retained thereon by means of cross-extending pins 32b. The angle or dog-leg shaped lift member or piece 34 is at its upper end secured as by weld metal or a set screw on the foot portion 320 to rotate or turn therewith. The lift member 34 is adapted to be swung from a lowermost position of FIG. 13 to an uppermost out-of-the-way position, such that its lower end is above the floor-engaging operating level of the driven rollers or wheels 15, 16.

As shown in FIG. 31, the piston rod 30b of the motor P may be positively energized in its down stroke to move the member 34 to its downmost position. By closing switch S to energize solenoid C the control valve V is opened to introduce a positive fluid flow from the line k to the fluid motor P,. On the other hand, when the switch S is opened to de-energize the solenoid C the valve V, is closed to exhaust fluid in the motor P through outlet j. This permits a spring-induced return of the piston rod 30b to its upper position and of the member 34 to its upwardly swung out-of-the-way position. The switch S is automatically operated and is shown as a micro switch positioned on the platform of the control and guide unit B (see FIGS. 16 and 18) for closing movement when a side-positioned lug or finger 67b engages it during a forward movement of piston rod 143, draw bar 135 and a backwardly extending switch-operating side arm 67. The switch S is opened when the finger 67b disengages it during the backward stroke or movement of the piston rod 143.

A positive and automatic control of the spacing advance of the nailing unit A for each back and forth run across a room is effected by means of back-positioned control and guide unit B (see FIGS. 15 to 18). The unit B has a support frame and table structure 115 and sidepositioned pairs of floor-engaging, motor-driven, wheels or rollers 116. A reversible, direct-current operated, speed-reducing electric motor unit M similar to the motor unit M is shown carried by the frame 115 and, through the agency of a pair of gear sprockets 118 and 120 and chain 119 (see FIG. 15), positively drives or activates a pair or side-positioned wheel driving shafts and 125' (see also FIG. 17). Each shaft 125, 125 has a pair of the floor-engaging wheels or rollers 116 secured thereon. The shaft 125' is actuated through the agency of sprocket 126 of the shaft 125, chain 127 and sprocket 128. The drive motor M, for the unit B is operated in substantial synchronism with the drive motor M of the unit A, in the sense that both units should move at the same rate of speed along the floor surface C.

The front end of the unit B has a variable-position draw bar coupling assembly connection with the back end of the unit A. Draw bar and fluid motor or cylinder P are swingably mounted at their back ends to provide a somewhat floating type of horizontal movement and that is operatable to activate and deactivate drive .motor M for the unit B, as controlled by a threeway switch S Although an in time or synchronized operation of the motors M, and M may be accomplished in a number of ways, I have in FIGS. 16, 18 and 31 shown one form of arrangement which utilizes a three-way switch S as actuated or controlled by the piston rod 143 of the motor unit P When the motor M of the unit A is energized, for example, to move it towards the righthand side of a room, this causes the fluid motor P to swing on its pivot 138 to thus cause the piston rod 143, side-extending switch arm 68 and vertically extending switch operating finger 68a to swing to the right. This closes one contact of the switch S to thus energize motor M in the same direction as motor M and produce movement of the unit B to the right with the unit A. On the other hand, when movementof the unit A is initiated towards the left-hand side of the room, the lag of the unit B will cause switch finger 68b to contact the leftcontact of the switch S and energize motor M in its reverse direction and move unit B towards the left side of the room. The thus initiated movements of the motor M are continued as long as the motor M, is energized to move the unit A in a given direction. Once the unit A stops, then the light switch closing lag with respect to the unit B is obviated and the switch 8,, moves to its central neutral or stop position thus deenergizing the motor M of the unit B. With reference to FIGS. 15, 16 and 18, transversely extending switch arm 68 is secured at its one end to the housing of the fluid motor P for movement therewith and at its other end carries the vertical or upright switch operating finger 68a.

The circuit of FIG. 31 shows a manual primary switch S, that may be carried for actuating the motors M, and M, as of a double pole reversing type, with one set of contacts for energizing the motors to rotate clockwise, with another set for energizing the motor to rotate them counterclockwise. The third position of the switch is an open (braking) position. It will be noted that the electrical connections between motor M, which is employed to move the unit A across a room and motor M, which is employed to move the unit B are such that the switch S serves to provide a simultaneous reversal of the electrical connections to the motor M Since switches S and 40a are simple connect and disconnect switches, it is immaterial to which side of the current source a, b they are connected.

The spaced distance between the units A and B may be adjusted manually or by fluid motor P (see FIG. after a latch member 150 of a position lock unit F of FIG. 22 has been lifted out of locking or latching en-.

gagement with respect to an aligned pair of slot portions 156a in connector channel member 156, or latch arm 168 of the assembly of FIG. 28 has been lifted out of locking or latching engagement with respect to latching notch or slot portions 168a of latching arm 168. Fluid motor P may be utilized to advance the unit A to a desired operating position for each movementsweep or board-nailing run across the room.

The unit B is provided with a pair of back-positioned, vertically mounted, opposed, guide rollers 130 which are adapted to engage and ride along a vertical flange of an angular-shaped guide member, rail or piece 131 (see FIG. 15) that may be bolted or nailed or otherwise temporarily secured to extend along the width of the room within which the apparatus is to operate. Each guide roller 130 is rotatably carried on a boltlike stub shaft 132 that is secured by nuts 133 to extend down-.

wardlyfrom the table 115 and ride below a limit strip 131a that is weld-secured to thervertical guide flange of the member 131. The strip 131a prevents the back end of the unit B from riding up off the guide flange of the member 131. A positive stationary guide means is thus provided for the apparatus during the full scope of operation of the nailer unit A within a floor area represented by or proportioned to the available coupling adjustments that may be accomplished in varying the spacing between the units A and B.

In nailing a course or run of floor boards or members 7, unit A is advanced to within a few feet of the end of the run adjacent a wall of the room. At this time, the unit A may be stopped by opening manual control switch S, which may be mounted on top of the frame of the unit A. The unit B stops automatically in the manner previously explained. At this time, the sidepositioned control unit or attachment D is removed from the then leading side of the unit A and its head part 100 is rotated approximately 225. The control unit D is then in its now upside-down relation attached to the opposite side of the unit A ready for a return movement of the apparatus. The manual switch S, is now closed to actuate the motor M, in its original direction to complete the nailing of thelast few feet, until the unit A reaches the side wall of the room. At this time, the switch S, may be opened and shifter switch S manually closed. This activates the fluid motor P to advance the piston rod 143 forwardly. After the piston rod 143 has advanced to its full forward position of FIG. 16, a switch operating lug or projecting finger 67b on the back end of switch operating arm 67 engages and closes micro switch S, of FIGS. 16 and 31 to energize solenoid C,,. It will be noted that the arm 67 is secured at its front end to extend backwardly from the angle-shaped bracket orhead member 140.

Referring particularly to FIG. .31, the closing actuation of the switch S causes the solenoid C to open the valve V and, as shown in FIG. 13, results in a downward-outward actuation of the piston rod 30b to raise the front end of the unit A through the agency of the foot of lift member 34. At this time, the guide rollers 35 are in a forward out-of-the-way position and thus, a new run or course of board members 7' may be inserted. The forward movement of the piston rod 143 pushes or moves about three inches forwardly to thus cause the same amount of forward movement of connected parts, including the parts 140, 141, 155, 156, 151 and 152 as well as the forward unit A. After a new run of board members 7' has been inserted, switch S of FIG. 31 is then manually moved to a closed position to energize solenoid C and positively move the shifter piston rod 143 in a back or return stroke. This moves the unit A backwardly. If desired, a mechanical con nection (not shown) may be provided between the switches S and S,, to cause the switch S to close first to energize solenoid C and by opening valve V pro duce a positive unlatching of the connector bar 156 through the agency of a downward movement of the piston rod 191 of the fluid motor P see also FIG. 22. This is only a momentary action and the switch 5,, is then opened again as the switch S completes its movement to afully closedposition.

The full closing of the switch S actuates solenoid C, and piston rod 143 to move it in its return or back stroke within the motor P During this movement, the latch under the tension of the pair of hold-down springs 189, then rides into the next or succeeding latching slot 156a, see FIG. 24. It will be apparentthat the switch 8,, may be a separate manual switch and operated in the manner above indicated. The distance be tween adjacent slots 156a is about 2% inches, but the pull-back is about three inches. When the latch 150 engages the next adjacent or rearward slot 156a in the connector bar 156 and locks in position therein, the cylinder P then pulls the unit .A back about threefourths of an inch to bring guide rollers 35 into an engaging position with respect to a flooring member 7' of a new run (see FIG. 1) and, at the same time, bring a board 7 of the new run tightly against a previously nailed flooring board 7.

The forward or outward stroke of the piston rod 143 is primarily to advance the machine A for the next succeeding board run. Switch S may be momentarily energized to advance the piston rod 143. A manual switch (not shown) may be connected in parallel with the switch S for, in the event of a jam, advancing the piston rod 143 of fluid motor or cylinder P and thus the unit A, to enable a repair of jamming without shifting the piston of cylinder P The switch S is normally in a closed position to operate the hammer motor P it is momentarily opened by the forward movement of finger projection 67a (see FIG. 16) as effected to the shifter piston rod and is retained in an open position until the finger 67a, on the return stroke of the piston rod 143, again engages the switch S to close it. The hammer 78 may be de-activated through the deactivation of the solenoid C and control valve V by opening switch 8 only when the drive motors are deactivated and during parts of the operation in which a new run of board members is being inserted. An additional manual switch (not shown) may be used in parallel with switch S in the circuit diagram of FIG. 31 to enable a separate manual actuation of the hammer if, at any particular time, it is desirable to so do.

When the apparatus is used for nailing-down a single floor or in other words, a floor directly on joists, about 5 to 6 feet of flooring should be laid for initially positioning the units A and B and the guide bar or channel 131. An adjustable channel type of coupling assembly E, such as illustrated in FIGS. to 26, will require starting the operation about five feet from the back wall adjacent to and along which the apparatus is adapted to move. On the other hand, an A-frame or scissors structure E, such as illustrated in FIGS. 28 to 30, permits starting about four feet from the back wall.

Centrally positioned, forwardly backwardly extending draw bar 135 has a slidable mounting on the frame 115 along the bottom reaches thereof, see particularly FIGS. 15 to 17. A cross-extending strap member 136 has a central, offset portion or recess slightly wider than the width of the bar 135 to permit this bar to also move horizontally for position control of unit B employing switch S of FIG. 16. The strap member 136 slidably receives the front end portion of the bar 135 and slidably mounts it in position on the front end portion of the under side of the table of frame 1 15. The bar 135 has a closed-end elongated slot 135a, (see FIG. 17) therealong which is engaged by a vertically positioned slide block or element 134 (see also FIG. 19) that is carried on a vertical stem, stud or pin shaft 138. The block 134 is carried on the stem 138 by a cotter pin and washer assembly 138a adjacent the under side of the frame 115. The upper end of the stem 138 is threaded to receive a nut 139 and to threadably fit within the bore of a mounting lug 114 that is secured to a vertical extension 115a of the frame 115, as by weld metal (see FIGS. 15 and 16). A clevis 146 is secured to the back end of the housing'of the fluid motor P, to swingably mount or float it on the stern 138 between the nut 139 and a spacer sleeve 147. It will be apparent that the bar 135 may be moved longitudinally forwardly and backwardly within the extent of the slot 135a, as guided in such movement by the stern 138 and the block 134 that operates within the slotted portion 135a.

Like connector bar 80 of the unit A, the draw bar 135 of the unit B also serves as a connector bar and, at its front end, has an angle-shaped mounting bracket or head member 140 on whose bottom flange a crossextending, rounded, mount or rod piece 141 is secured as by weld metal to extend transversely thereacross. Movement of the bar is effected by a fluid motor, such as reciprocating pneumatic motor P that is mounted on the upper side of the table of the frame 1 15 and that has a forwardly extending piston rod 143. As shown particularly in FIG. 15, the forward end of the rod 143 is threaded and extends through the vertical or upper flange portion of the head member and is secured thereto in an adjustable relation by a pair of nuts 144.

As shown in FIGS. 1 and 2, connector bar 80 of the nailer unit A is pivotally secured at its front end on a vertical nut and bolt assembly 82 which extends through the table or platform 11 of the unit. The bar 80 projects backwardly along the upper side of the table 11 through a back end of the unit. A recessed crossextending straplike bracket or guide member 83 extends across an intermediate portion of the connector bar 80 and is secured to the upper side of the table 11 by bolts 83a that also mount inner flange portions of the pair of backwardly positioned bearings 20'. As noted, the front pair of bearings 20 and the outer feet of the back pair of bearings 20' are secured on the platform or table 11 by bolts 21. The recess portion in the bracket 83 has a width greater than the width of the connector bar 80 (see FIG. 2) to permit the bar 80 to flexibly pivot about the assembly 82. The back end of the bar 80 has an upright flange portion 80a secured as by weld metal thereto, and pivotally secured to a back flange of a connector bracket or head member 81 of inverted angular-shape by a bolt and nut assembly 80b.

In the adjustable connector assembly represented by FIGS. 20 to 26, the connector head member 81 is removably and non-twistably secured to one (upper) connector channel or bar 156 by means of a pair of transversely spaced-apart screw and thumb nut assemblies 153, a cross-extending rodlike piece 152, a forwardly extending tab member 151, and a projecting web portion 156b that is integral with the connector bar 156. The piece 152 fits within the valley of an an gle-shaped portion of bracket part 81 and is weldsecured to the tab member 151. The tab member 151 is weld-secured on the web portion 156b to provide an integral construction therewith. A second (lower), slidably interfitting, channel-shaped connector member or bar 155 cooperates with the member 156 to provide an adjustable assembly E. The forward end of the lower member 155 (see FIG. 25) has a rectangular-shaped, boxlike, closed-off collar 160 weld-secured thereto to slidably guidably receive the back end of the upper or other cooperating member 156 therein. The upper member 156 has a channel-shaped, upwardly open collar 162 secured on its back end by bolt and nut assemblies 161 to slidably guidably receive the back end of the lower member 155 therein. As particularly shown in FIGS. 25 and 26, the connector members 155 and 156 have an interfitting, telescopic or complementary endwise slidable relation with respect to each other.

From the above, it will be apparent that the upper connector channel member 156 is secured at its front end l56b to the bar member 80 of the front nailing unit A. On the other hand, the lower channel member 155 is connected at its back end l55b to the draw bar member 135 of the back or control unit B.

Referring particularly to FIGS. 20 to 26, inclusive,

and FIG. 27, it will be notedthat the upper channelshaped connector bar member 156 is provided with cross-extending latching notches or recesses 156a at spaced locations along its opposed side flanges. At its rear end, the lower member 155 has a backwardly extending web portion l55b to which is weld-securedan inverted, angle-shaped, end connector bracket 145 that is weld-secured thereto to project backwardly therefrom and cooperate with a cross-extending or transverse rodlike part or element 141. As shown particularly in FIGS. Hand 24, the part or element 141 is sei cured by weld metal w to rest on a horizontal, forwardly extending, flange portion of an angle-shaped tie member 140 and is removably secured to the inverted connector bracket 145 by a pair of spaced-apart vertically through-extending, thumb nut and bolt assemblies 142.

The connector channel members or bars 155, 156 are adapted to be adjusted telescopically in and "out" with respect to each other, longitudinally between nailing unit A and control unit B. The connector bar members will at the start of a floor laying operation preferably be in their longitudinally minimized extending relationship. The distance between the notches 156a will be such as to permit a step by step increase in spacing between members 155 and 156 and thus, between the units A and B, that will substantially correspond to the width of a run or course of board members 7 that has been laid and nailed-down by a previous across-the-room-operation. This step by step increase in the elongation of the members or, in other words, in the spacing between the units A and B may be accomplished manually or more or less automatically. In this connection, latching, position change and locator unit F and assemblyE shown in FIGS. 20 to 24, inclusive, may be employed for a substantially automatic adjustment of the latched or extended relationship between the members -155 and 156. On the other hand, FIGS. 27 to 29, inclusive, illustrate a simple manual type of assembly E for effecting adjustment between such members. i

, The latching, position change and locator unit F is shown. in FIGS. 20- to 24 as securely mounted on an upper leaf 185a of a hingelike mounting means or member assembly 185, as by weld metal w. The other or lower leaf l85b of the hinge member 185 is shown secured, as by weld metal w, to the top face of the boxlike. collar 160. Unit F has a table or platform 186 which rests on the upper leaf 185a and which carries a fluid motor P an electric solenoid C,, a control valve V and a positive pressure fluid supply inlet 188. A vertical frame portion 187 of the platform 186, at its upper end, mounts one end of a tension spring 189 thereon. Thespring 189 is mounted at its lower end on the under side of the lower, channel-shaped connector 155 by an eyelet in a floating steel dowel or cross-extending rod 155a that is suspended beneath the channel 155 by the spring. As shown in FIG. 23, a pair of springs 189 thus urge the platform or table 186 downwardly towards the assembly E to thus maintain angle-shaped latching finger member 150 within aligned latching slots 1560 of the upper connector bar member 156.

The latching finger 150 is weld-secured to the platform 186 and has a downwardly projecting flange that is lifted out of an aligned pair of cooperating slots 156a when positive fluid pressure is applied to the upper end of the air cylinder or fluid motor P to thusmove its piston rod 191 downwardly and tilt the. table, as shown in FIG. 22, about the hinge 185. Thiswpermits the slideadjustmentbetween the cooperating connector barmembers and 156, aseffected by slide bar l35andpiston 143 of the unit B (see FIG. 15) and.the backward stroke of fluid motor P The embodiment of FIGS. 28 and 29: shows an A" or scissors frame type of connectingassembly E that is particularly suited for a shorter overall extent or area of runs. It employs a pair of channel-shaped, upright, leg members and 166 that, at their lower ends, are weld-mounted on hinged connector brackets or parts 84and 142 and, at their upper ends, are pivotally connected by a hinge 167. The bracket 84" will take the place of bracket 151 of FIG. 21 and the bracket142. will take the place of the bracket 145 of the same figure. A rectangular latch arm assembly 168 is shown (see FIG. 29) that is pivotally mounted substantially intermediate the vertical height of the leg member 166 by a cross-extending bolt and pin assembly 169. The other leg member 165 is shown provided with a latch retention pin 170 that'extends across between its side flanges and is adaptedto fit within one of a series of undercut slot pairs 168a in sidemembers of the arm assembly 168, A tension spring 172 is shown connected at its upper end on a cross-extending loose pin 171 and atits lower end to a cross-extending pin 173 that is positioned between the flanges of the leg. member 165. It will be apparent that the pin 171 resiliently resists the raising of the latch arm 168, but permits its manual raising to enable the latch pin 170 to be latched within a selected one of the slot pairs 168a.

The spacer assembly represented by the A-frame of FIG. 28 is particularly suitable for use when starting a nailing operation, in that it permits the nailing unit A to be operated after about fourfeet ofboard runs have been manually nailed in position. Thereafter, the double channel system or assembly E of FIGS. 20 and 21 or additional double or single channel spacer bars may be used for obtaining a maximum extent of board run coverage before it becomes necessary to lift the guide rail 131 and secure it in a new, advanced position.

The operation involved in advancing the trailing unit A for approximately a board width, e.g., about 3 inches as applied to the assembly of FIGS. 20 and 21, involves manual movement of electric. switch S to one closed position (FIG. 31), energization of solenoid C in one direction, opening of valve V to one position and .a forward, one-step, positive movement of the piston rod 143 of the fluid motor P The forwardmovement of the piston rod 143 causes the lug 67b of the. switch arm 67 to close the switch S and thus energize solenoid C opening valve V and positively activating the lifter piston rod 30b. This results in the unit A and theassembly E being moved forwardly with respect to the unit B about 3 inches, with the unit B being backwardly tilted off the working floor surface 7 (see FIG. 13). At this time, there is a gap of about 3 inches between the leading floor board 7 and the guide rollers 35. Assuming the use of 2% inch face floor boards, although other face boards may be used by employing a different spacing of. the slots l56a.in the assembly E, a new floor board run 7 is now inserted between the. guide rollers 35 and the last laid run 7 to leave about three-fourths inch remaining space in the area.

After the board run 7 is inserted in position, switch S is moved to a second closed, current-flow, reversing position to energize solenoid C in an opposite direction, to shift valve V for supplying air to the opposite side of the cylinder P and thereby initiate a 3 inch back stroke of the piston rod 143. At the same time, switch 8,, is momentarily closed to energize solenoid C open valve V and give a positive fluid pressure upward movement to the spacer bar lifter piston rod 191 to thus lift or raise the latch 150 out of a cooperating slot 156a. When the piston rod 143 is moved in its back stroke by the fluid motor P it thus draws the assembly E and the unit A backwardly. The latch shift of 150 with respect to the slots 156a will occur first becuase it presents the least resistance A drawing back of the unit A will occur last becuase of the greater resistance to its movement. It will be noted that the motor or cylinder P the control valve V and the solenoid C are identical with the motor P the valve V and the solenoid C except that the motor P may have a larger cylinder than the motor P The latch 150 slides to the right on the connector bar 156 on the backwardly declining portion thereof (see FIGS. 21 and 24) to move into abutment with the shoulder of the next adjoining slot 156a. At this time, the latch 150 is then drawn into full engagement within the slot by the tension pull of the pair of springs 189 to positively lock the connector bars 155 and 156 together. Since the cylinder P has a remaining three-fourths of an inch to move the piston rod 143 backwardly, it thereafter pulls the unit A back this same distance, causing the guide rollers 35 to engage the board 7' and the board 7 to engage the previously laid board 7. All of this is accomplished while the unit B is held stationary by the track rail 131 (see FIGS. and 17).

The schematic of FIG. 31 diagrammatically shows a suitable operating system for apparatus of the disclosure. A source of electrical energy or power such as direct current may be supplied by lines a and b to a circuit and through a reversing switch S, to motors M, and M which respectively are employed to move the units A and B in step across the room or along a course or run of board members 7' that is being laid. Switches S, and S are employed for alternately energizing both motors M, and M,. In this connection, S, may be a manual switch mounted on either the unit A or B, and S, may be an automatic switch such as the micro switch (shown in FIGS. 9, l0 and 11) that is operated during the movment of the wheeled, side-positioned, movement-controlling unit D. Switches S, and 40a may be normally closed with switch S, (of FIG. 9) or alternately switch 37 of FIG. 1, and switch 400 being opened under previously explained operating conditions. Switches S, and S, are alternate (manual and automatic) switches that may be used for electrically energizing solenoid C, for moving control valve V, from a closed-off position, from the standpoint of positive fluid pressure flow from line i, to an open position for energizing fluid cylinder or motor P,.

When solenoid C, is energized, it moves the valve V, to an open position and actuates fluid motor P, to provide a positive down stroke of the nailer head 50. When the valve V, is closed by de-energization of the solenoid C,, the head 50 is returned to its upper or starting position by spring loading of the motor P,, and fluid from the motor is exhausted through the outlet j. The positive "down" stroke drives a nail such as 8 of FIG. 6 into a board member 7 that is being laid. S represents a manual switch that may be used at any time by the operator and particularly, when the control unit D has been removed from a side of the nailing unit A to finish a nailing operation closely adjacent to one side of a room. The switch S may be an automatically operated micro switch, as shown in FIG. 9, that is periodically closed by cam means 97 or 97 of the control unit D. The operation of the cam 97 or 97' is such as to time the closing of stud switch S at positions at which the unit A has its nailer head 50 in alignment with a sJud or support member, such as 5 of the floor assembly. Where a subfloor is used, the closing of the switch 8,, may be set to occur at any desired spacedapart positions therealong.

After a line of board members 7' has been secured or nailed in position with respect to a previously nailed and laid row of floor members 7, then the nailing unit A may be tilted backwardly by the mechanism shown in FIGS. 13 and 14, and as operated by fluid motor I of FIG. 31. This operation, as previously indicated, may be effected by automatically closing switch S to energize solenoid C and move control valve V from a closed and fluid exhausting position (through outletj) to a preliminary position at which positive fluid flow from line k is introduced to one side of the fluid motor or cylinder P to move its piston rod 30b outwardly and cause its lift part or member 34 to tilt the unit A, as shown in FIG. 13. This facilitates the insertion of or the preliminary manual laying of the next succeeding row, course or line of board members 7', while the guide rollers 35 are in a raised out-of-the-way position. Thereafter, the switch S, may be opened in order that the spring loading of the motor P, may withdraw the piston 30b and cause the unit A to fully rest on the floor assembly C. At this time, peripheral groove portions 35a of the guide rollers 35 will be moved by fluid motor I into engagement with the forward, longitudinally extending tongue portions of the course or run of board members 7' that are to be laid.

Before the above operations are accomplished, it is desirable to carry-out the previously described onestep forward advance or extension of either the assembly E of FIGS. 20 to 26 or theassembly E' of FIGS. 29 and 30. It will be noted that a four-way valve V is used for controlling the operation of the fluid motor I under positive fluid pressure as to both the backward and forward movements of its piston rod 143 through the agency of the solenoid C and a dual-pole currentflow-reversing electric switch S The logical sequence of operation is for the assembly E to be expanded or extended one notch after each cross-nailing operation has been accomplished on a run of board members 7'. An important feature is thefact that, as shown in FIG. 15, the unit B serves as a positive guide unit for the nailing unit A, while a run of floor members of a suitable width is being nailed to form part of a floor assembly C.

The hammer 78 may be operated by an air cylinder or motor having about a two inch stroke and of a type such as manufactured and sold by Bimba of Monee, Ill., see the double-acting, pivot type; see No. l-DP of page 16 of catalog No. 1266-8. It has a piston providing a positive forward or down stroke movement and a positive return or upper stroke. Four way control valve V is opened by closing automatic switch S, to energize solenoid C The automatic switch S may be closed (see FIGS. 15, 16 and 18) when, for example,

the piston rod 143 is extended, indicating that a board member 7' that has been manually laid in position does nothave its tongue portion in a proper interfitting relation with the groove portion of previously laid floor member 7 and thus, it is necessary to hammer itin place. The switch S remains closed until a hammer blow'corrects the condition.

'Again referring to FIG. 31, switch S may be manually closed to energize solenoid C and move four-way control valve V to a position at which positive fluid flow is introduced from line k through branch line 1 to one end of the cylinder P to move the piston rod 143 to the right hand position shown in FIG. 31. On the other hand, when the piston rod 143 is to be advanced forwardly (to the left ofFIG. 31. the solenoid C, is deenergized or energized by an opposite direction of current flow as effected by the switch S to thus cause a positive fluid flow from line k through branch line m into the other end of the cylinder P The outlet j exhausts fluid from ends of the motor P that are opposite to the ends at which positive fluid pressure is being applied. Although apparatus of the invention has been shown as utilizing nail assemblies that are moved down the feed chute to present one drive-in element at each nailing stroke, it will be appreciated that the so-called nailer or board securing unit may be any suitable unit or means for securing board members in place and including a unit or means for feeding and manipulating metal clips and the like. The unit B in combination with the switch means S serves to sense an improper alignment of a board member 7' and to effect a correction thereof through the agency of the hammer. It will be apparent that a conventional flexible electric cable may be plugged-in or connected at one end to a wall receptacle or other suitable source of electric current and at its other end connected to leads a and b of the units. Also, a flexible hydraluic hose may be connected at one end to a pump system and at its other end to the line h of the units. By way of example, see the cable 53 and the hose S0 of my US. Pat. No. 3,619,895.

I claim:

1. In a mobile floor laying apparatus for back and forth movement on a previously laid floor area along an adjacent run of endwise-positioned floor members for progressively securing the floor members of the run'on under-support I members in an aligned-sidewiseengaging complementary-fitting relation along outer side edges of a previously laid floor member run of the floor area, a mobile floor member securing unit for back and forth movement along the adjacent line across the floor area, means cooperating with said securing unit for positively guiding it in an aligned relation during its back and forth movement, motor means carried by said securing unit for periodically moving it back and forth across the floor area while aligned by said guiding means, means carried by said securing unit for periodically securing floor members of the adjacent run on the under-support members in an aligned fitted relation along the outer side edges of the previously laid floor member run of the floor area, and means actuated in a timed relation to the back and forth movement of said securing unit for periodically actuating said securing means.

2. .In an apparatus as defined in claim 1, said means for positively guiding said securing unit being a backwardly positioned control unit, connector means connecting said securing unit in a forwardly spaced relation to said control unit, a guide rail secured on and extending along the previously laid floor area, and means carried by said control unit and having a rolling-guided relation with said guide rail for positively guiding said control unit during the back and forth movement of said securing unit.

3. In an apparatus as defined in claim 2, motor means carried by said control unit for moving it back and forth across the floor area with said securing unit, and means operating the motor means of said securing unit in a timed relation with respect to the motor means for said control unit.

4. In an apparatus as defined in claim 3, means for automatically stopping said respective motor means when an end of a floor member of the adjacent run is reached.

5. In an apparatus as defined in claim 1, means cooperating with said securing unit for tilting it backwardly to allow insertion of a new run of floor members along a previously laid run. a

6. In an apparatus as defined in claim 2, said connector means having means for advancing the spacing between said units one step for each back and forth movement of said units to. accommodate said securing unit to a new lengthwise run of floor members to be laid.

7. In apparatus as defined in claim 6, said means for advancing the spacing constituting a pair of longitudinal members, and latch means and spaced-apart latchreceiving slot portions adjustably connecting said members together with respect toeach other.

8. In an apparatus as defined in claim 7, said latch means having a fluid motor for moving it into and out of latching engagement with aligned slot portions.

9. In an apparatus as defined in claim 6, means associated with said space advancing means for sensing an improperly positioned floor member of a run to be secured in position.

10. In an apparatus as defined in claim 9, hammer means carried by said securing unit and actuated by said sensing means for driving the improperly positioned floor memberinto a properly aligned position.

11. In apparatus as defined in claim 1, said periodic actuating means comprising wheel means that is rotated during the back and forth movement of said securing unit, and said wheel means carrying a camoperated electrical switch that is adapted to energize said floor member securing means when it is closed.

12. In apparatus as defined in claim 1, a control unit for back and forth movement across the floor area in a backwardly positioned aligned relation with said securing unit, a telescopic'connecting bar member assembly between a rear end of said securing unit and said control unit, a motor-driven reciprocating bar member carried by said control unit and connected to a rear end of said connector bar assembly, a first mem ber of said connector bar assembly defining latching recess portions in a spaced relation therealong, and latching means operatively positioned on a second member of said connecting bar assembly and adapted to selectively latch-engage with said latching recess portions of said first member.

13. In apparatus as defined in claim 12, a latch actuating unit operatively carried by said second member of said bar assembly and adapted to move said latching means into and out of engagement with aligned latching recess portions of said first member, said reciprocating bar member of said control unit being adapted to advance said first and second members one additional space with respect to each other when said securing unit has made one traversal of the floor area, and said latch actuating unit being adapted to move said latching means out of engagement with an aligned recess portion before said reciprocating bar member advances said first and second members one additional space and thereafter to move said latching means into engagement with a successive recess portion when said first and second members of said assembly have been advanced in spacing one space with respect to each other,

14. In a mobile floor securing apparatus for back and forth movement on a previously laid floor area along a lengthwise run of floor board members being laid endwise for progressively securing the floor board members of the run on spaced-apart support members in an valigned-Sidewise-engaging complementary-fitting relation along an outer side edge of a previously laid floor board member run that is secured on the support members, a mobile board securing frame unit unit, means for actuating said securing frame unit for back and forth movement along the floor area, and means carried by said unit for de-energizing said motor means when said securing frame unit approaches the end of a board member of the run being laid.

l5. In an apparatus as defined in claim 14, board securing means and hammer means operatively carried by said securing frame unit, cam means carried by said securing frame unit and controlled by the back and forth movement of said unit for periodically actuating said board securing means when said frame unit reaches a properly aligned relation with respect to a support member on which a board member of the run is to be secured, and said hammer means having a hammer head to deliver a blow to a floor board member of the run being laid for properly aligning it with respect to the outer side edge of a floor board member of the previously laid run.

16. In a mobile floor laying apparatus for back and forth movement on a previously laid floor area long a lengthwise run of floor board members being laid endwise for progressively securing the floor board members of the run on spaced-apart cross-extending support members in an aligned-sidewise-engaging complementary-fitting relation along an outer side edge of a previously laid floor board member run that is secured on the crossextending support members, a mobile board securing frame unit and a mobile guide frame unit, means coupling said units respectively in a front and back aligned relation with respect to each other for coordinated back and forth movement along the floor area, motor means for actuating each of said frame units for synchronous back and forth movement along the floor area, and means carried by one of said units for de-energizing said motor means when said nailer frame unit approaches the end of a board member of the run being laid.

17. In an apparatus as defined in claim 16, said means for de-energizing said motor means being operatively carried by said board securing frame unit in an extending relation from a side thereof in the direction of movement of said frame units along the floor area.

18. In an apparatus as defined in claim 16, means for advancing said board securing frame unit in a step-bystep manner forwardly with respect to said guide frame unit after each completed movement of said frame units across the floor area.

19. In an apparatus as defined in claim 18, said coupling means having a pair of cooperating slide bar members one of which is connected to extend backwardly from said board securing frame unit and the other of which is connected to extend forwardly from said guide frame unit, latch and slot means between said slide bar members, and said means for advancing said board securing frame unit cooperating with said latch and slot means for at each step advancing said board securing frame unit about the width of a board member that is to be nailed in position.

20. In an apparatus as defined in claim 18, said coupling means having a complementary slidably interfitting pair of connector members between said board securing frame unit and said guide frame unit, latch and slot means for retaining said connector members in a preset cooperating position with respect to each other, means for releasing said latch and slot means from retention of said connector members, means carried by said guide frame unit for thereafter drawing back one of said connector members with respect to the other, said latch and slot means being adapted to then connect said connector members in a new advanced relation with respect to each other, and said drawing means being adapted to then move said board securing frame unit forwardly a distance corresponding to the distance of the previous draw back of said one connector member.

21. In an apparatus as defined in claim 16, a wheeled control unit adapted to be detachably mounted to alternatively extend sidewise from opposite sides of said board securing frame unit, said board securing frame unit having a nailer carried thereon for periodically nailing advanced portions of a board member of the run being laid to the cross-extending support members while the apparatus is being moved back and forth along the floor area, and means carried by said control unit for energizing said nailer at periodic intervals corresponding to the location of the support members.

22. In an apparatus as defined in claim 21, means carried by said control unit for energizing and deenergizing said motor means in accordance with the presence or absence of an endwise-extending floor member to be nailed in position.

23. In a mobile floor laying apparatus for back and forth movement on a previously laid floor area along an adjacent run of floor board members being laid endwise for progressively securing the floor board members on under-support members in an aligned-sidewiseengaging complementary fitting relation along outer side edges of a previously laid floor member run of the floor area, a mobile floor member securing unit and a mobile guide frame unit for back and forth movement across the floor area, coupling means connecting a back end of said securing unit to a front end of said guide unit in a swingably maintained spaced-apart relation with respect to each other, means cooperating with the previously laid floor area for positively guiding said mobile guide unit across the room, reversible motor means on said mobile securing unit for alternately moving it back and forth along the floor area, reversible motor means on said guide unit for alternately moving it back and forth along the floor area, switch means operatively carried by said mobile guide unit for actuating its said motor means in the same direction as said 

1. In a mobile floor laying apparatus for back and forth movement on a previously laid floor area along an adjacent run of endwise-positioned floor members for progressively securing the floor members of the run on under-support members in an alignedsidewise-engaging complementary-fitting relation along outer side edges of a previously laid floor member run of the floor area, a mobile floor member securing unit for back and forth movement along the adjacent line across the floor area, means cooperating with said securing unit for positively guiding it in an aligned relation during its back and forth movement, motor means carried by said securing unit for periodically moving it back and forth across the floor area while aligned by said guiding means, means carried by said securing unit for periodically securing floor members of the adjacent run on the under-support members in an aligned fitted relation along the outer side edges of the previously laid floor member run of the floor area, and means actuated in a timed relation to the back and forth movement of said securing unit for periodically actuating said securing means.
 2. In an apparatus as defined in claim 1, said means for positively guiding said securing unit being a backwardly positioned control unit, connector means connecting said securing unit in a forwardly spaced relation to said control unit, a guide rail secured on and extending along the previously laid floor area, and means carried by said control unit and having a rolling-guided relation with said guide rail for positively guiding said control unit during the back and forth movement of said securing unit.
 3. In an apparatus as defined in claim 2, motor means carried by said control unit for moving it back and forth across the floor area with said securing unit, and means operating the motor means of said securing unit in a timed relation with respect to the motor means for said control unit.
 4. In an apparatus as defined in claim 3, means for automatically stopping said respective motor means when an end of a floor member of the adjacent run is reaChed.
 5. In an apparatus as defined in claim 1, means cooperating with said securing unit for tilting it backwardly to allow insertion of a new run of floor members along a previously laid run.
 6. In an apparatus as defined in claim 2, said connector means having means for advancing the spacing between said units one step for each back and forth movement of said units to accommodate said securing unit to a new lengthwise run of floor members to be laid.
 7. In apparatus as defined in claim 6, said means for advancing the spacing constituting a pair of longitudinal members, and latch means and spaced-apart latch-receiving slot portions adjustably connecting said members together with respect to each other.
 8. In an apparatus as defined in claim 7, said latch means having a fluid motor for moving it into and out of latching engagement with aligned slot portions.
 9. In an apparatus as defined in claim 6, means associated with said space advancing means for sensing an improperly positioned floor member of a run to be secured in position.
 10. In an apparatus as defined in claim 9, hammer means carried by said securing unit and actuated by said sensing means for driving the improperly positioned floor member into a properly aligned position.
 11. In apparatus as defined in claim 1, said periodic actuating means comprising wheel means that is rotated during the back and forth movement of said securing unit, and said wheel means carrying a cam-operated electrical switch that is adapted to energize said floor member securing means when it is closed.
 12. In apparatus as defined in claim 1, a control unit for back and forth movement across the floor area in a backwardly positioned aligned relation with said securing unit, a telescopic connecting bar member assembly between a rear end of said securing unit and said control unit, a motor-driven reciprocating bar member carried by said control unit and connected to a rear end of said connector bar assembly, a first member of said connector bar assembly defining latching recess portions in a spaced relation therealong, and latching means operatively positioned on a second member of said connecting bar assembly and adapted to selectively latch-engage with said latching recess portions of said first member.
 13. In apparatus as defined in claim 12, a latch actuating unit operatively carried by said second member of said bar assembly and adapted to move said latching means into and out of engagement with aligned latching recess portions of said first member, said reciprocating bar member of said control unit being adapted to advance said first and second members one additional space with respect to each other when said securing unit has made one traversal of the floor area, and said latch actuating unit being adapted to move said latching means out of engagement with an aligned recess portion before said reciprocating bar member advances said first and second members one additional space and thereafter to move said latching means into engagement with a successive recess portion when said first and second members of said assembly have been advanced in spacing one space with respect to each other.
 14. In a mobile floor securing apparatus for back and forth movement on a previously laid floor area along a lengthwise run of floor board members being laid endwise for progressively securing the floor board members of the run on spaced-apart support members in an aligned-sidewise-engaging complementary-fitting relation along an outer side edge of a previously laid floor board member run that is secured on the support members, a mobile board securing frame unit, motor means for actuating said securing frame unit for back and forth movement along the floor area, and means carried by said unit for de-energizing said motor means when said securing frame unit approaches the end of a board member of the run being laid.
 15. In an apparatus as defined in claim 14, board securing means and hammer means operatively carried by saiD securing frame unit, cam means carried by said securing frame unit and controlled by the back and forth movement of said unit for periodically actuating said board securing means when said frame unit reaches a properly aligned relation with respect to a support member on which a board member of the run is to be secured, and said hammer means having a hammer head to deliver a blow to a floor board member of the run being laid for properly aligning it with respect to the outer side edge of a floor board member of the previously laid run.
 16. In a mobile floor laying apparatus for back and forth movement on a previously laid floor area long a lengthwise run of floor board members being laid endwise for progressively securing the floor board members of the run on spaced-apart cross-extending support members in an aligned-sidewise-engaging complementary-fitting relation along an outer side edge of a previously laid floor board member run that is secured on the cross-extending support members, a mobile board securing frame unit and a mobile guide frame unit, means coupling said units respectively in a front and back aligned relation with respect to each other for coordinated back and forth movement along the floor area, motor means for actuating each of said frame units for synchronous back and forth movement along the floor area, and means carried by one of said units for de-energizing said motor means when said nailer frame unit approaches the end of a board member of the run being laid.
 17. In an apparatus as defined in claim 16, said means for de-energizing said motor means being operatively carried by said board securing frame unit in an extending relation from a side thereof in the direction of movement of said frame units along the floor area.
 18. In an apparatus as defined in claim 16, means for advancing said board securing frame unit in a step-by-step manner forwardly with respect to said guide frame unit after each completed movement of said frame units across the floor area.
 19. In an apparatus as defined in claim 18, said coupling means having a pair of cooperating slide bar members one of which is connected to extend backwardly from said board securing frame unit and the other of which is connected to extend forwardly from said guide frame unit, latch and slot means between said slide bar members, and said means for advancing said board securing frame unit cooperating with said latch and slot means for at each step advancing said board securing frame unit about the width of a board member that is to be nailed in position.
 20. In an apparatus as defined in claim 18, said coupling means having a complementary slidably interfitting pair of connector members between said board securing frame unit and said guide frame unit, latch and slot means for retaining said connector members in a preset cooperating position with respect to each other, means for releasing said latch and slot means from retention of said connector members, means carried by said guide frame unit for thereafter drawing back one of said connector members with respect to the other, said latch and slot means being adapted to then connect said connector members in a new advanced relation with respect to each other, and said drawing means being adapted to then move said board securing frame unit forwardly a distance corresponding to the distance of the previous draw back of said one connector member.
 21. In an apparatus as defined in claim 16, a wheeled control unit adapted to be detachably mounted to alternatively extend sidewise from opposite sides of said board securing frame unit, said board securing frame unit having a nailer carried thereon for periodically nailing advanced portions of a board member of the run being laid to the cross-extending support members while the apparatus is being moved back and forth along the floor area, and means carried by said control unit for energizing said nailer at periodic intervals corresponding to the location of the support members.
 22. In an apparatus as defined in claim 21, means carried by said control unit for energizing and de-energizing said motor means in accordance with the presence or absence of an endwise-extending floor member to be nailed in position.
 23. In a mobile floor laying apparatus for back and forth movement on a previously laid floor area along an adjacent run of floor board members being laid endwise for progressively securing the floor board members on under-support members in an aligned-sidewise-engaging complementary fitting relation along outer side edges of a previously laid floor member run of the floor area, a mobile floor member securing unit and a mobile guide frame unit for back and forth movement across the floor area, coupling means connecting a back end of said securing unit to a front end of said guide unit in a swingably maintained spaced-apart relation with respect to each other, means cooperating with the previously laid floor area for positively guiding said mobile guide unit across the room, reversible motor means on said mobile securing unit for alternately moving it back and forth along the floor area, reversible motor means on said guide unit for alternately moving it back and forth along the floor area, switch means operatively carried by said mobile guide unit for actuating its said motor means in the same direction as said motor means of said securing unit, said switch means having an open central position and right and left hand closed positions, and means cooperating with said coupling means for closing said switch means after said securing unit has moved a short distance to the right or left and for moving said switch means to its open central position when said securing unit has stopped in its movement.
 24. In an apparatus as defined in claim 23, nailing means operatively carried by said securing unit for periodically nailing the floor members in position, hammer means on said securing unit for hammering floor members to be laid into an aligned closely fitting relation with outer side edges of the floor members of the previously laid run, locating means carried by said guide unit and cooperating with said coupling means for advancing said securing unit forwardly with respect to said guide unit for operating on a new run of floor members to be laid, and switch means carried by said guide unit and cooperating with said locating means for actuating said hammer.
 25. In an apparatus as defined in claim 24, said locating means cooperating with said coupling means for expanding it by one position each time said securing unit has moved in one direction across the floor area, and said coupling means having latching means cooperating with said locating means for advancing said securing unit one step with respect to said guide unit after each across-the-floor movement of said securing unit.
 26. In an apparatus as defined in claim 24, said locating means comprising a reciprocating fluid motor swingably secured on said guide unit and operatively connected to said coupling means. 